Lab Markers that Matter
This short guide highlights the labs most useful for understanding energy, sexual function, cognition, body composition, and long-term health. Targets vary by lab and medical history. This is educational, not personal medical advice.
Metabolic health (energy, weight, diabetes risk)
A1c, fasting glucose, fasting insulin: Reveal early insulin resistance, even before diabetes.
Lipid panel (LDL, HDL, triglycerides): Foundation for cardiovascular risk. Helpful clue for insulin resistance and dietary patterns.
Hormones (sexual function, mood, muscle)
Testosterone panel:
Total Testosterone: best drawn in the morning
Free Testosterone: high quality assay
SHBG: explains symptoms when total T looks “normal”
LH & FSH: Distinguish pituitary signal vs. testicular production issues.
Estradiol (sensitive): Libido, mood, bone; balance matters on TRT.
Prolactin: Elevated levels can blunt libido/erections.
PSA: Prostate screening is a must.
Hematocrit/Hemoglobin: Watch for elevated red blood cells, especially on testosterone therapy.
Thyroid (metabolism, energy, mood)
TSH, Free T4, and Free T3: determine if suboptimal thyroid function is causing symptoms.
Liver, kidney, electrolytes (medication safety, recovery)
Comprehensive Metabolic Panel (CMP):
AST and ALT: for liver function
Creatinine and eGFR: for kidney function
Electrolytes like potassium and sodium: for hydration and muscle function.
Inflammation
hs-CRP: General inflammation signal linked with cardiovascular risk; interpret alongside blood pressure and lipids.
Nutrient status (fatigue, cognition, immunity)
Vitamin D (25-OH): Bone, muscle, immune health.
Vitamin B12: Nerve health, energy.
Ferritin: Low may relate to fatigue; high may reflect inflammation or other issues.
How to prepare for accurate results
Fast 8-12 hours for metabolic and lipid testing (water is fine).
Morning draw (7–10 a.m.) for baseline testosterone.
If using injectable TRT, draw a trough (right before the next dose) unless instructed otherwise.
Pause high-dose biotin 24-48 hours before thyroid labs.
Avoid strenuous workouts and heavy alcohol the day before. Both can skew enzymes and inflammation markers.
How often to check
Baseline: Everything that fits age and health profile.
On or considering TRT: Baseline labs 8-12 weeks after starting or adjusting dose. Every 3-6 months during the first year of therapy. Every 6-12 months once stable.
Metabolic markers (A1c, lipids): At least annually; potentially every 6 months during active weight, medication, or lifestyle changes.
Vitamin D, B12, ferritin: Typically annually. When appropriate, recheck based on symptoms, season, and supplementation.
When a result matters most
Low energy, poor recovery, or fat-loss plateau: Check thyroid, testosterone (total/free/SHBG), vitamin D, ferritin, and CMP.
ED or low libido: Testosterone panel, estradiol (sensitive), prolactin, plus metabolic markers.
Bottom line
You can’t optimize what you don’t measure. A clear lab plan paired with symptoms, exam findings, sleep, and nutrition supports personalized care for stronger erections, steadier energy, and mood, as well as long-term heart and brain health.
Ready to get started?
Book a telehealth consult, complete labs, and review a personalized plan with a licensed provider.